Convert CONFIG_SCSI to Kconfig

This converts the following to Kconfig:
   CONFIG_SCSI

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/configs/minnowmax_defconfig b/configs/minnowmax_defconfig
index 96a45aa..a64a0a3 100644
--- a/configs/minnowmax_defconfig
+++ b/configs/minnowmax_defconfig
@@ -47,6 +47,7 @@
 CONFIG_OF_CONTROL=y
 CONFIG_REGMAP=y
 CONFIG_SYSCON=y
+CONFIG_SCSI=y
 CONFIG_CPU=y
 CONFIG_MMC=y
 CONFIG_MMC_PCI=y